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The present invention relates to network interface adapters for coupling a host computer to a computer network, and more specifically to a multi-mode network interface adapter that is capable of operating in at least a diagnostic mode, a sleep mode, and a run-time mode.
The connection of computers to computer networks to facilitate the exchange of information between and among client computers and servers coupled to the networks has become commonplace. A host computer is typically communicably coupled to a network via a device commonly referred to as a network interface adapter, which may comprise logic disposed on a motherboard with host logic or alternatively disposed on a network interface card that may be electrically coupled to the host computer via mating connectors.
The ability to detect errors and maintain the operability of network interface adapters cannot be over emphasized where computers are routinely requested by users to access information and communicate with other users over a network. Accordingly, the ability to detect problems within a network interface adapter and to maintain the operability of the network interface adapter over a variety of operational conditions is extremely important in various business and commercial environments.
Moreover, the ability of computers to conserve or otherwise manage the power that they consume has become increasingly important. In a typical power management scheme, a computer or at least a certain number of components incorporated therein is powered-down when the computer is not in use for an extended time. A computer or sub-system in this condition may be referred to as operating in a xe2x80x9clow-power statexe2x80x9d or a xe2x80x9chost operating system absent state.xe2x80x9d Full power is then restored to the computer when it is required for use. A computer in this alternate condition may be referred to as operating in a xe2x80x9cfull-power statexe2x80x9d or a xe2x80x9chost operating system present state.xe2x80x9d
Although such power management schemes have enhanced the energy efficiency of computers, current power management techniques have drawbacks in that they are not easily adapted for use in network computing systems. For example, a computer connected to a network typically monitors the network for data packets. If the computer detects a data packet, then it generally either rejects the data packet or accepts and processes the data packet. However, if the computer implements a power management application that causes it to enter the low-power state after a period of non-use, then that computer in the low-power state may be incapable of monitoring the network for data packets. As a result, data packets that are addressed to that computer may go undetected and be inadvertently lost.
Not only may data packets be inadvertently lost on the network, but a computer in the low-power state may also lose its communications link to the network. For example, such a computer may be incapable of renewing the lease of its IP address within the lease period. As a result, that computer may inadvertently lose both its current IP address and its communications link to the network.
It would therefore be desirable to have a network interface adapter that includes self-diagnostic capability, the ability to support network functions even if the host computer is in the host operating system absent state, and to provide typical network functions when the host is operational and operating in the host operating system present state.
In accordance with the present invention, a network adapter is described that is operational in at least three modes. In a first mode of operation, the network adapter executes diagnostic software routines to determine whether predetermined functions associated with the network adapter are operational. Status information is reported to the host processor as a consequence of the execution of the self-diagnostic routines. In a second mode of operation, the network adapter responds to network messages and transmits messages onto the network in response to a signal from the host processor indicating that the host processor is entering the host operating system absent state. In a third mode of operation, the network adapter provides normal run-time functions and passes messages received by the network adapter over the network to the host processor and transmits messages received from the host processor over the network in accordance with the applicable transfer protocols. In a fourth mode of operation, the network adapter executes additional diagnostic software routines to determine whether predetermined functions relating to the interoperability of the network adapter and a host computer communicably coupled thereto are operational.
Other features, functions, and aspects of the invention will be evident from the detailed description of the invention that follows.